Women's Health

Tools & Resources

Radioactive Iodine Uptake Test

Guide

A radioactive iodine
uptake (RAIU) test uses a
radioactive tracer and a special probe to measure how
much tracer the
thyroid gland absorbs from the blood. The test can show how much tracer is
absorbed by the thyroid gland. The RAIU test often is done along with a thyroid scan, which shows if the tracer is evenly spread in the gland. This
helps your doctor know if the thyroid gland is working properly. The
radioactive tracer commonly used in this test is iodine.

A
radioactive iodine uptake test is done to find problems with how the thyroid
gland works, such as
hyperthyroidism.

How To Prepare

Tell your doctor if you:

Take any medicines regularly. Be sure your
doctor knows the names and doses of all your medicines. Your doctor will
instruct you if and when you need to stop taking any of the following medicines
that can change the RAIU test results:

Are allergic to any medicines, such as iodine.
But even if you are allergic to iodine, you will likely be able to have this
test because the amount used in the tracer is so small that your chance of an
allergic reaction is very low.